The present invention relates to a liquid crystal display cell and, more particularly, to a liquid crystal display panel providing an improved display contrast.
The thickness of conventional liquid crystal display cells, in particular, twisted nematic liquid crystal display cells, is typically about 10 .mu.m owing to their electro-optic response characteristics. However, it was difficult to uniformly apply a suitable high electric field to such a thin liquid crystal cell. Therefore, polarized light applied was not able to satisfy Mauguin limit of d.multidot..DELTA.n&gt;&gt;.lambda. where .DELTA.n is the double refractive index of a liquid crystal layer, d is the thickness of the liquid crystal layer, and .lambda. is the wavelength of applied light, in the case where the polarized light is applied to the liquid crystal layer along the direction parallel to or perpendicular to the longitudinal axes of liquid crystal molecules in the liquid crystal layer.
Consequently, the polarized light cannot twist to a required degree, say, to a right angle to thereby provide elliptic polarization with rotational polarization. Under the circumstances, when in addition to a polarizer an analyzer is used to analyze light passing through the liquid crystal layer, it appears that transmission light is colored owing to the interference by double refraction even in the case of cross or parallel structure with respect to the polarizer and the analizer.
Disadvantageously, this led to poor display contrast ratio and poor viewability.